1. Field of the Invention
The present invention pertains to medical equipment, and more particularly, to a device and method for attaching an ultrasound catheter to an ultrasound transducer which mitigates against breakage of the ultrasound transmission member, and which facilitates ultrasound energy propagation.
2. Description of the Prior Art
A number of ultrasound systems and devices have heretofore been proposed for use in ablating or removing obstructive material from blood vessels. Ultrasound catheters have been utilized to ablate various types of obstructions from blood vessels of humans and animals. Successful applications of ultrasound energy to smaller blood vessels, such as the coronary arteries, requires the use of relatively small diameter ultrasound catheters which are sufficiently small and flexible to undergo transluminal advancement through the tortuous vasculature of the aortic arch and coronary tree. However, because of its small diameter, the ultrasound transmission member which extends through such catheters is particularly susceptible to breakage and losses in the transmitted ultrasound energy.
Breakage of ultrasound transmission members often occurs near the proximal end thereof, generally at the coupling between the ultrasound catheter coupling and the ultrasound transducer. This is believed to be because energy concentrations are highest at these points. Thus, any external forces applied to the ultrasound transmission member in this region may result in stresses exceeding the elastic limit of the ultrasound transmission member.
External forces may be inadvertently and undesirably applied to the ultrasound transmission member by pressing upon, pushing, pulling, torquing, bending or bumping the ultrasound transmission member coupling during use of the ultrasound catheter. Such forces when applied to the ultrasound catheter coupling area result in limited ultrasound energy transmission through the ultrasound transmission member. If ultrasound energy is being transmitted by the ultrasound transmission member at the instant such forces are applied thereto, stresses occur which commonly result in breakage of the ultrasound transmission member.
Thus, there still exists a need to mitigate against breakage of the ultrasound transmission member by reducing mechanical stress applied to the proximal end of the ultrasound transmission member during operation.
It is an object of the present invention to provide an ultrasound catheter system that mitigates against breakage of the ultrasound transmission member by reducing mechanical stress applied to the proximal end of the ultrasound transmission member during operation.
It is another object of the present invention to provide an improved connection between the ultrasound catheter and the ultrasound transducer.
It is yet another object of the present invention to improve the propagation of ultrasound energy by limiting and minimizing impact of undesirable external forces.
In order to accomplish the objects of the present invention, there is provided a connector assembly for connecting an ultrasound transducer to an ultrasound catheter that has an ultrasound transmission member extending longitudinally therethrough. The connector assembly has an ultrasound transducer having a transducer housing, and an extension having a proximal end attached to the distal end of the transducer housing. The connector assembly also includes a ring assembly having an inner ring and an outer ring that is received inside the bore of the outer ring. The connector assembly also includes a catheter knob having a proximal end that is removably coupled to the extension. The inner ring is moved from a non-supporting position with the extension positioned inside the bore of the inner ring, to a supporting position with the catheter knob positioned inside the bore of the inner ring.